// Copyright (c) 2001 Daniel C. Nuffer
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// Copyright (c) 2001-2011 Hartmut Kaiser
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#if !defined(BOOST_SPIRIT_ITERATOR_REF_COUNTED_POLICY_MAR_16_2007_1108AM)
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#define BOOST_SPIRIT_ITERATOR_REF_COUNTED_POLICY_MAR_16_2007_1108AM
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#include <boost/spirit/home/support/iterators/multi_pass_fwd.hpp>
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#include <boost/spirit/home/support/iterators/detail/multi_pass.hpp>
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#if defined(BOOST_HAS_THREADS)
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#include <boost/detail/atomic_count.hpp>
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#endif
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#include <cstdlib>
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namespace boost { namespace spirit { namespace iterator_policies
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{
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///////////////////////////////////////////////////////////////////////////
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// class ref_counted
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// Implementation of an OwnershipPolicy used by multi_pass.
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//
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// Implementation modified from RefCounted class from the Loki library by
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// Andrei Alexandrescu.
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///////////////////////////////////////////////////////////////////////////
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struct ref_counted
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{
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///////////////////////////////////////////////////////////////////////
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struct unique // : detail::default_ownership_policy
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{
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void swap(unique&) {}
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// clone is called when a copy of the iterator is made, so
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// increment the ref-count.
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template <typename MultiPass>
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static void clone(MultiPass& mp)
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{
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if (0 != mp.shared())
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++mp.shared()->count;
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}
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// called when a copy is deleted. Decrement the ref-count. Return
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// value of true indicates that the last copy has been released.
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template <typename MultiPass>
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static bool release(MultiPass& mp)
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{
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return 0 != mp.shared() && 0 == --mp.shared()->count;
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}
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// returns true if there is only one iterator in existence.
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// std_deque StoragePolicy will free it's buffered data if this
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// returns true.
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template <typename MultiPass>
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static bool is_unique(MultiPass const& mp)
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{
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return 0 == mp.shared() || 1 == mp.shared()->count;
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}
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template <typename MultiPass>
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static void destroy(MultiPass&) {}
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};
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////////////////////////////////////////////////////////////////////////
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struct shared
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{
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shared() : count(1) {}
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#if defined(BOOST_HAS_THREADS)
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boost::detail::atomic_count count;
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#else
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std::size_t count;
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#endif
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};
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};
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}}}
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#endif
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